BACKGROUND: Adult periodontitis is a destructive disease that may lead to tooth loss and decreased quality of life. Currently, little is known regarding the impact of surgical periodontal therapy on tooth loss and oral-specific health- related quality of life (OQOL). GOAL: The aim of this R01 proposal is to initiate a periodontal outcomes study among the members of Washington Dental Service (WDS), a not for-profit dental insurance plan. AIMS: Primary aim: To determine the impact common periodontal procedures on tooth loss and OQOL in a population of 1561 WDS patients with periodontitis using a prospective cohort design. Secondary aims: (i) Relate OQOL to tooth loss, periodontal treatment history, and periodontal disease characteristics. (ii) Investigate subgroups, dose- response relationships, site-specific relationships between periodontal treatments and tooth loss, and specific treatments such as osseous grafts and site-specific anti-microbial treatments. (iii) Study the impact of patient characteristics (e.g., smoking, diabetes) on the therapeutic response. (iv) Estimate the association between non-surgical periodontal therapy and tooth loss and OQOL. (v) Assess the feasibility of conducting randomized trials of simple periodontal treatments among an insured population. PROPOSED STUDY: Study Design: A prospective cohort study (n=1,561;starting date: January 2002), with a retrospective component (n=20,275 patients starting in 1993). Patient clinical characteristics, outcomes, procedure data, and OQOL will be obtained from patient-survey data (mail and telephone) and the WDS data warehouse. Generalized estimating equation models, with time dependent covariates, will be used to relate tooth loss and OQOL to the periodontal treatment history and patient characteristics. PRELIMINARY DATA: The feasibility and design of this study were determined by a periodontal outcome study in Kaiser Permanente Dental Plan, a mail survey of WDS patients regarding patient risk factors for periodontitis, a retrospective analysis of WDS data, and a pre-testing of the OQOL instrument. SIGNIFICANCE: Information will be obtained regarding the tooth loss and OQOL that is associated with real-world clinical decisions, in a broad range of periodontitis patients, in specialist practice settings. This information can help determine in what area of periodontal research definitive clinical trials may offer the greatest contribution.